Patent GB-537831-A (GB)
Title: Manufacture of azo-dyestuffs
IPC: C09B43/04
Filed: 1940-01-05
Abstract: 537,831. Dyes.. SOC. OF CHEMICAL INDUSTRY IN BASLE. Jan. 5, 1940, Nos. 304 and 305. Convention dates, Jan. 5, 1939 and Dec. 4, 1939. [Classes 2 (iii) and 15 (ii)] Monoazo dyes, free from sulphonic acid groups and of the general formula wherein A and B represent nuclei of the benzene series, y and z each represent H, alkyl or substituted alkyl, the nucleus A carries at least one substituent capable of enhancing the acidity of a phenolic hydroxy group and the amino group is in p-position to the azo group. Specified acidity-enhancing substituents are halogen atoms and nitro, cyano, sulphone, sulphonamide, carboxyl, ketone and carboxylic amide groups. Specified aminoazo dyestuffs used as starting materials are 4-nitroaniline # aniline, N-dimethyl-, N- diethyl-, N-methyl-, N-ethyl- or N-methyl N-butyl-aniline, 2-toluidine, 2-anisidine, 3- chloraniline or 3- chloro-N-dimethyl-aniline ; 3- nitroanilineaniline, 2-toluidine or 2-anisidine ; 2-nitro-aniline # aniline, N - dimethylaniline or 2-toluidine; 3-nitro-2-aminotoluene # aniline ; 2-, 3- or 4-chloroanilineaniline; aniline-2-, 3- or 4-methylsulphone # aniline ; aniline-3- methylsulphone # N - dimethylaniline ; 4- nitro-2-chloroaniline or 2 : 5-dichloroaniline # aniline or N-dimethylaniline ; 2 : 6-dichloro-4- nitroaniline # N - dimethylaniline ; 3 - nitro - 5 - chloroaniline, 2 : 4 - dinitroaniline, 2 : 4 - dinitro - 6 - chloroaniline or 4 - cyanoaniline # aniline ; 4 - cyanoaniline # N - dimethylaniline ; aniline - 4 - sulphodimethylamide or aniline - 4 - carboxylic acid or its ethylamide #  aniline ; 2 - nitroaniline - N - ethyl - N - # - hydroxyethyl - aniline ; 3 - nitroaniline # N - di(#-hydroxyethyl)aniline; N-di (#-hydroxyethyl) - 3 - toluidine ; N - ethyl - N - # - chlorethyl - aniline or N - ethyl - N - # - methoxyethyl - aniline ; 4 - nitroaniline # N - ethyl - N - # - hydroxyethyl - aniline. The nitration may be effected by treatment with conc. or dilute nitric acid, especially in presence of sulphuric, glacial acetic or chlorosulphonic acid or of acetic anhydride, a halogenated hydrocarbon or dioxane ; primary or secondary amino groups in the starting materials may be acidylated before or after the nitration. The products containing diazotizable amino groups may be diazotized and further coupled with components in substance or on the fibre. In examples, (1) the dyestuff, 4-nitroaniline # aniline, is nitrated at or below 0‹ C. with cone. nitric acid in conc. sulphuric acid ; the neutralized product may be dispersed, e.g. with turkey red oil or sulphite cellulose liquor for dyeing acetate artificial silk full reddish yellow shades, fast to light ; the dyestuff, 4-chloroaniline # aniline (coupled as the #- methanesulphonic acid and hydrolysed may be similarly nitrated or may be first acetylated and then nitrated in sulphuric acid, dioxane, tetrachlorethane or glacial acetic acid ; (2) the dyestuff, 3-nitro-2-aminotolueneaniline, is nitrated at 0-10‹ C. in conc. sulphuric acid ; the neutralized product dyes acetate artificial silk brown-yellow ; the dyestuffs, 2-nitroaniline # - N-dimethyl- or N-ethyl-N-#-hydroxyethyl-aniline may be similarly nitrated ; in the latter case the hydroxy group may be converted into the sulphuric acid ester group before nitration, with or without subsequent saponification to restore the hydroxy group ; (3) the dyestuff, 4 - nitro - 2 - chloro - or 2 : 6 -dichloro - aniline - aniline, is similarly nitrated in conc. sulphuric acid ; the neutralized products dye acetate artificial silk yellow ; (4) the dyestuff, 3-nitroaniline # aniline, is similarly nitrated in sulphuric acid ; the product, neutralized if desired, dyes acetate artificial silk yellow ; a similar product is obtainable by acetylating the parent dyestuff with acetic anhydride, nitrating the acetylation product with nitric acid in glacial acetic acid and saponifying to the acetyl group ; (5) the dyestuff 3- or 4- nitroaniline # N-dimethylaniline, is nitrated at about 10‹ C. with nitric acid in conc. sulphuric acid or with nitrosyl chloride in tetrachlorethane ; the neutralized products due acetate artificial silk brown ; (6) the dyestuff, 4-chloroanilineaniline, is nitrated at about 0‹ C. with nitric acid in conc. sulphuric acid ; the neutralized product dyes acetate artificial silk yellow ; the dyestuffs, aniline-2- or 4-methylsulphone # aniline or aniline-3-methylsulphone # N-dimethylaniline may be similarly nitrated ; the similarly nitrated products from the dyestuffs 4-nitroaniline- 2-anisidine or 3-chloro- N-dimethylaniline, dye acetate artificial silk orange to red ; (7) acetate artificial silk yarn is dyed a brilliant yellow by treatment in a soap solution, heated during ¥ hour to 80-85‹ C. and so maintained for a further “ hour. containing the dyestuff of (1) above dispersed with Turkey red oil, sulphite cellulose liquor or a sulphonated residue from the manufacture of benzaldehyde. The Specification as open to inspection under Sect. 91 comprises also the nitration of the dyestuffs of the above general formula containing sulphonic groups, such as sulphanilic acid # aniline or N-dimethylaniline and 4-nitroaniline-2-sulphonic acid- N-diethylaniline, the products being suitable for dyeing wool and silk. This subject-matter does not appear in the Specification as accepted.